1. Field of the Invention:
This invention relates to a reverberatory furnace, and more particularly to a reverberatory furnace for melting metal and holding molten metal.
2. Description of the Prior Art:
Reverberatory furnaces are widely used for melting aluminum or aluminum alloy. Generally, a burner is mounted on a side wall oppositely to, and far from an opening well to supply metal to be molten, in the reverberatory furnace. Thus, it is avoided that metal to be molten contacts directly with flame of the burner. Or a refractory shield member is arranged between the burner and the opening well to supply metal to be molten so as to avoid the direct contact with flame of the burner. This type of furnace is called as "opening well reverberatory furnace."
In use of the reverberatory furnace, metal to be molten is dropped into molten metal through the opening well. Metal receives heat from molten metal, and is molten without directly contacting with flame of the burner. Before the reverberatory furnace is used in such a manner, metal as base is supplied into the interior of the reverberatory furnace to form a molten metal pool, or molten metal is supplied into the reverberatory furnace to form the molten metal pool, from another furnace or vessel.
Metal is supplied into the pool through the opening well. Heat is transferred from the pool to the metal to melt the latter. Metal is thus molten without direct contact with flame of the burner. If metal contacts directly with flame of the burner, oxide is formed on metal such as aluminum. The molten metal oxide is slag or impurity. It should be removed, and so it causes decrease of yield rate. Accordingly, it is required to avoid direct contact of metal with flame of the burner.
However, in the reverberatory furnace, temperature decreases with the distance from the burner. Accordingly, the temperature of the molten metal is the lowest at the opening well which is farthest from the burner. It takes much time to melt metal dropped into the molten metal at the opening well. The melting efficiency of the reverberatory furnace becomes low.
Hitherto, to improve the melting efficiency of the reverberatory furnace, the molten metal therein was manually or mechanically stirred so as to move from the neighbourhood of the burner to the opening well. However, the manual stir takes much labor, and it is dangerous. And mechanical elements are often damaged in the mechanical stir.